Treatment outcomes in older patients with metastatic breast cancer receiving palbociclib plus an aromatase inhibitor: a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: This summary describes an article published in the medical journal Frontiers in Oncology in September 2023. The article reports results from a study that looked at breast cancer treatments for older patients aged 75 years or older. The study focused on a type of cancer called HR+/HER2- metastatic breast cancer. HR+/HER2- stands for hormone receptorpositive/human epidermal growth factor receptor 2-negative. This study evaluated whether older patients with this type of cancer benefited from the combination of two medicines - palbociclib and an aromatase inhibitor - compared with taking an aromatase inhibitor alone. HOW WAS THE STUDY IN THIS SUMMARY CARRIED OUT?: The Flatiron database contains medical records for people with cancer in the US. This study used deidentified health care information from this database. 'Deidentified' means that all information that could identify an individual was removed to protect individuals' privacy. People in this study received treatment in routine care and not in a clinical trial. WHAT DO THE RESULTS MEAN?: Older patients who took palbociclib plus an aromatase inhibitor lived longer than those who took an aromatase inhibitor alone. Older patients who took palbociclib plus an aromatase inhibitor also lived longer without their cancer getting worse and started chemotherapy later than those who took an aromatase inhibitor alone. These results support using palbociclib plus an aromatase inhibitor as the first treatment for patients aged 75 years or older with HR+/HER2- metastatic breast cancer.

Prolonging the lives of African-Americans with metastatic breast cancer by adding palbociclib to an aromatase inhibitor in routine clinical practice: a plain language summary of a real-world database study.

WHAT ARE THE KEY TAKEAWAYS?: This study used de-identified medical information from the Flatiron Database. This database contains healthcare information on people with cancer treated by doctors in the United States but personal information is removed to maintain privacy. Medical information for people who received certain treatments in routine clinical practice or real-world setting was included in the study. This study showed that in the real-world setting, African-Americans with HR+/HER2- MBC lived longer when receiving palbociclib with an AI than with an AI alone. Also, the study showed that African-Americans treated with palbociclib plus an AI lived longer without their cancer getting worse than those treated with an AI alone. WHAT WAS THE MAIN CONCLUSION REPORTED BY THE RESEARCHERS?: These results support the use of palbociclib with an AI as a first treatment for African-Americans with HR+/HER2- MBC. Clinical Trial Registration: NCT05361655 (ClinicalTrials.gov).

Real-world comparative effectiveness of palbociclib plus aromatase inhibitor in HR+/HER2- metastatic breast cancer.

Aim: Provide real-world data on palbociclib as evidence of effectiveness in patient populations from routine clinical practice. Methods: This was a retrospective, observational cohort study of patients with HR+/HER2- metastatic breast cancer treated with palbociclib plus aromatase inhibitor (AI) or AI alone as first-line therapy within the US Oncology Network. Results: Patients treated with palbociclib plus AI (n = 838) versus AI alone (n = 450) had a numerically longer median overall survival (42.1 vs 35.7 months; hazard ratio [HR] = 0.90 [95% CI: 0.75-1.07]; p = 0.117) and a significantly extended real-world progression-free survival (21.0 vs 15.7 months; HR = 0.75 [95% CI: 0.64-0.88]; p = 0.0002) after normalized inverse probability treatment weighting. Conclusion: These real-world results support the use of palbociclib plus AI as first-line treatment in routine clinical practice for patients with HR+/HER2- metastatic breast cancer.

What is this summary about? This summary describes how well palbociclib works when used with an aromatase inhibitor in the real-world setting for people with a certain type of breast cancer that has spread to other areas of the body. Palbociclib stops cancer cells from growing and dividing. An aromatase inhibitor prevents the body from making the hormone estrogen, which is needed for certain types of breast cancer cells to grow. Palbociclib with an aromatase inhibitor is a standard first treatment used for people with this type of breast cancer that needs estrogen to grow and has spread to other areas of the body. In clinics, doctors may not always prescribe the two treatments together. The study wanted to find out if using the two treatments together worked better than using an aromatase inhibitor alone in the real-world setting. What were the results? The results suggest that in this population of patients treated in a real-world setting, people with breast cancer that needs estrogen to grow and has spread to other areas of the body who were treated with palbociclib plus an aromatase inhibitor lived longer without their cancer getting worse than those treated with an aromatase inhibitor alone. What do the results of the study mean? The results support the use of palbociclib with an aromatase inhibitor as a first treatment for breast cancer that has spread to other areas of the body, rather than an aromatase inhibitor only.

Real-world treatment patterns for palbociclib plus an aromatase inhibitor, or an aromatase inhibitor alone, for patients with metastatic breast cancer in the Flatiron Database.

There are limited real-world comparative effectiveness data for palbociclib plus an aromatase inhibitor (AI) as a first-line (1L) treatment examining endpoints that require long term follow-up and post 1L progression. The Flatiron Health Analytic Database was used to characterize treatment and dosing patterns in patients with hormone receptor-positive/human epidermal growth factor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) receiving palbociclib plus an AI vs an AI alone in routine US clinical practice. In addition, time to chemotherapy (TTC) and real-world progression-free survival (rwPFS) when combining 1L and second-line of therapy (rwPFS2) were assessed. Of 1324 patients who received palbociclib plus an AI between February 3, 2015 and March 31, 2020, 1110 (83.8%) started palbociclib at the recommended 125 mg/day dose. After stabilized inverse probability treatment-weighting (sIPTW), median TTC in patients treated with palbociclib plus an AI and AI alone was 37.4 months (95% confidence interval [CI], 33.7-40.7) and 29.2 months (95% CI, 26.8-33.5), respectively (hazard ratio [HR] = 0.77 [95% CI, 0.69-0.86], P < .0001); median rwPFS2 was 32.6 months (95% CI, 29.4-35.2) and 20.7 months (95% CI, 18.9-22.6), respectively (HR = 0.62 [95% CI, 0.54-0.70], P < .0001). Sensitivity analyses with propensity score matching showed similar results to sIPTW analyses. Results from this large real-world study examining additional effectiveness outcomes beyond 1L rwPFS and overall survival support the use of palbociclib plus an AI as a 1L treatment for patients with HR+/HER2- mBC.

Palbociclib Combined with an Aromatase Inhibitor in Patients with Breast Cancer with Lung or Liver Metastases in US Clinical Practice.

A cyclin-dependent kinase 4/6 inhibitor combined with endocrine therapy is the standard of care for patients with hormone receptor-positive/human epidermal growth factor 2-negative (HR+/HER2-) metastatic breast cancer (mBC), but real-world effectiveness data for patients with lung or liver metastases are limited. This retrospective study included data from the US Flatiron Health database of patients with HR+/HER2- mBC and lung or liver metastases treated with first-line palbociclib (PAL) plus an aromatase inhibitor (AI) or an AI alone in routine clinical practice. Overall survival (OS) and real-world progression-free survival (rwPFS) were assessed. A total of 891 patients were included (622 with lung metastasis, 376 with liver metastasis, and 107 with both lung and liver metastasis). After stabilized inverse probability of treatment weighting to balance patient characteristics, PAL + AI versus AI alone was associated with significantly prolonged OS (HR = 0.62; p < 0.001) and rwPFS (HR = 0.55; p < 0.001) in patients with lung metastases and numerically longer OS (HR = 0.73; p = 0.056) and significantly longer rwPFS (HR = 0.57, p < 0.001) for those with liver metastases. Overall, PAL + AI versus AI alone was associated with prolonged OS and rwPFS in routine clinical practice, supporting the use of first-line PAL + AI for patients with HR+/HER2- mBC with lung and/or liver metastases.

Real-world treatment patterns and effectiveness of palbociclib plus an aromatase inhibitor in patients with metastatic breast cancer aged 75 years or older.

Background: Elderly patients are generally underrepresented in oncology clinical trials; therefore, real-world data are needed to inform clinical management of elderly patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (mBC). This subanalysis of the P-REALITY X study (NCT05361655) evaluated palbociclib treatment patterns and comparative effectiveness of palbociclib plus an aromatase inhibitor (AI) versus an AI alone among patients with HR+/HER2- mBC aged ≥ 75 years treated in routine clinical practice in the United States. Methods: This retrospective observational cohort study used electronic health records from the Flatiron Health Analytic Database. Palbociclib treatment patterns, overall survival (OS), real-world progression-free survival (rwPFS), and time to chemotherapy (TTC) were evaluated. Three methods were used for comparative analyses: (1) an unadjusted analysis, (2) stabilized inverse probability treatment weighting (sIPTW; primary analysis), and (3) propensity score matching (PSM; sensitivity analysis). Results: A total of 961 patients aged ≥ 75 years with HR+/HER2- mBC were identified who started palbociclib plus an AI (n = 313) or an AI alone (n = 648) as first-line (1L) therapy between February 2015 and March 2020 (data cut-off: September 30, 2020). Among patients in the palbociclib plus an AI group with a documented palbociclib starting dose (n = 306), approximately 75% started palbociclib at 125 mg/day, and approximately 40% experienced dose adjustment. After sIPTW, patients treated with palbociclib plus an AI versus an AI alone had significantly improved OS (median of 43.0 vs. 32.4 months; hazard ratio [HR], 0.66 [95% confidence interval (CI), 0.51-0.84]; P = 0.0007), rwPFS (median of 20.0 vs. 15.0 months; HR, 0.72 (0.59-0.89); P = 0.0021), and TTC (median of 40.2 vs. 27.4 months; HR, 0.69 [0.55-0.87]; P = 0.0014). These significant improvements in OS, rwPFS, and TTC remained consistent in the unadjusted analysis and after PSM. Conclusion: This real-world comparative analysis demonstrated that 1L palbociclib plus an AI is associated with improved effectiveness compared with an AI alone among patients with HR+/HER2- mBC aged ≥ 75 years. These findings support palbociclib plus an AI as a standard-of-care 1L treatment for elderly patients with HR+/HER2- mBC.

Real-World Effectiveness of Palbociclib Plus Aromatase Inhibitors in African American Patients With Metastatic Breast Cancer.

BACKGROUND: Disparities in survival and clinical outcomes between African American and White patients with breast cancer (BC) are well documented, but African American patients have not been well represented in randomized clinical trials of CDK4/6 inhibitors. Real-world studies can provide evidence for effective treatment strategies for underreported patient populations. PATIENTS AND METHODS: This retrospective analysis of African American patients with HR+/HER2- metastatic breast cancer (mBC) from the Flatiron Health longitudinal database evaluated treatments for patients with BC in routine clinical practice in the US. Patients initiated first-line therapy with palbociclib plus an aromatase inhibitor (AI) or AI alone between February 2015 and March 2020. Outcomes assessed included overall survival (OS) and real-world progression-free survival (rwPFS) until September 2020. RESULTS: Of 270 eligible patients, 127 (median age 64 years) were treated with palbociclib + AI, and 143 (median age 68 years) were treated with an AI. Median follow-up was 24.0 months for palbociclib + AI and 18.2 months for AI-treated patients. Median OS was not reached (NR; 95% CI, 38.2-NR) in the palbociclib + AI group versus 28.2 months (95% CI, 19.2-52.8) in the AI group (adjusted HR, 0.56; 95% CI, 0.36-0.89; P = .013). Median rwPFS was 18.0 months (95% CI, 12.4-26.7) in the palbociclib + AI group and 10.5 months (95% CI, 7.0-13.4) in the AI group (adjusted HR, 0.74; 95% CI, 0.47-1.17; P = .199). CONCLUSION: This comparative analysis of palbociclib + AI versus AI alone indicates that palbociclib combined with endocrine therapy in the first line is associated with improved effectiveness for African American patients with HR+/HER2- mBC in real-world settings. TRIAL NUMBER: NCT05361655.

Real-World Tumor Response of Palbociclib in Combination With an Aromatase Inhibitor as First-Line Therapy in Pre/Perimenopausal Women With Metastatic Breast Cancer.

BACKGROUND: Limited real-world data exist regarding the efficacy of palbociclib in combination with endocrine therapy in pre/perimenopausal women with metastatic breast cancer. OBJECTIVE: We aimed to compare real-world tumor responses among pre/perimenopausal women who initiated palbociclib plus an aromatase inhibitor (AI) or AI monotherapy as first-line treatment for hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer. METHODS: This retrospective observational cohort study (NCT05012644) used electronic health record data from The US Oncology Network. Tumor responses were determined based on treating clinicians' assessments of radiologic evidence for changes in disease burden. Normalized inverse probability treatment weighting was used to balance baseline characteristics between treatment cohorts. RESULTS: Of 196 pre/perimenopausal women, 116 and 80 were in the palbociclib plus AI cohort and AI cohort, respectively. Real-world response rates (complete or partial response) were 52.1% and 46.2%, respectively (odds ratio, 1.27 [95% confidence interval 0.72‒2.24]). Among patients with one or more tumor assessments on treatment, real-world response rates were 60.0% in the palbociclib plus AI cohort (n = 103) and 49.9% in the AI cohort (n = 71; odds ratio, 1.51 [95% confidence interval 0.82‒2.77]). CONCLUSIONS: This real-world analysis suggests that pre/perimenopausal patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer appear more likely to respond to palbociclib plus AI versus AI alone as first-line therapy, which may support the combination as a standard-of-care treatment for this patient population.

Palbociclib (Ibrance^®) is a medicine for patients with metastatic breast cancer (MBC). Metastatic means that the cancer has spread to other places in the body. Patients take palbociclib with hormone therapy, such as an aromatase inhibitor (AI). Palbociclib plus an AI is a treatment for a type of MBC called HR+/HER2‒ MBC. HR+/HER2‒ stands for hormone receptor positive, human epidermal growth factor receptor 2 negative. Researchers wanted to observe responses to treatment in routine clinical practice among women with HR+/HER2­ MBC who had not reached menopause. A response is if a tumor shrinks or disappears after treatment. This study used healthcare information reported in electronic medical records of patients seen by doctors in The US Oncology Network. This study included 196 women with HR+/HER2­ MBC who had not reached menopause and had not received prior treatment for MBC. A total of 116 women received palbociclib plus an AI, and 80 women received an AI alone. Researchers used standard statistical approaches to balance baseline characteristics between the two treatment groups. These adjustments made the groups more similar so that researchers could compare treatment responses. Sixty percent of patients who took palbociclib plus an AI responded, compared with 50% of patients who took an AI alone. These results suggest that palbociclib plus an AI may benefit women with HR+/HER2‒ MBC who have not reached menopause.

Psychosocial Wellbeing among Patients with Breast Cancer during COVID-19.

The impact of coronavirus disease 2019 (COVID-19) on the wellbeing of breast cancer (BC) patients is not well understood. This study described psychosocial problems among these patients in the United States (US) during the COVID-19 pandemic. Data were collected from BC patients via an online self-report survey between 30 March-6 July 2021 to assess the prevalence of COVID-19 diagnosis history and potential depression, health-related quality of life, COVID-related stress, and financial toxicity. Patients with early-stage (eBC) and metastatic (mBC) disease were compared. Of 669 patients included in the analysis, the prevalence of COVID-19 diagnosis history (10.9% versus 7.7%) and potential depression (33.7% versus 28.3%) were higher in mBC than eBC patients. Patients with eBC (versus mBC) had higher scores on nearly all Functional Assessment of Cancer Therapy-Breast scales (all, p < 0.001). For the Psychological Impact of Cancer subscales measuring negative coping strategies, the emotional distress score was the highest (9.1 ± 1.8) in the overall sample. Comprehensive Score for Financial Toxicity scores were higher in eBC than in mBC patients (24.2 ± 11.3 vs. 21.3 ± 10.2, p < 0.001). Overall, the COVID-19-related stress score was highest for danger/contamination fears (8.2 ± 5.6). In conclusion, impairments to psychosocial wellbeing among patients during the pandemic were observed, particularly financial toxicity and poor mental health and emotional functioning, with greater problems among mBC patients.

Real-world comparative effectiveness of palbociclib plus letrozole versus letrozole in older patients with metastatic breast cancer.

BACKGROUND: Palbociclib, the first available cyclin-dependent kinase 4/6 inhibitor, plus endocrine therapy is approved for hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (MBC). This study compared real-world effectiveness of palbociclib plus letrozole versus letrozole in older patients with MBC in US clinical practice. METHODS: This retrospective analysis included patients from the Flatiron Health longitudinal database. Overall, 796 women with HR+/HER2- MBC aged ≥65 years starting palbociclib plus letrozole or letrozole as first-line therapy between February 2015 and September 2018 were included. Patients were evaluated from treatment start until December 2018, death, or last visit, whichever came first. Real-world progression-free survival (rwPFS), overall survival (OS), and real-world best tumor responses (rwBTR) were endpoints. Stabilized inverse probability treatment weighting (sIPTW) balanced patient characteristics. RESULTS: After sIPTW, 450 patients treated with palbociclib plus letrozole and 335 treated with letrozole were included; median age was 74.0 years. Median rwPFS was 22.2 (95% CI, 20.0-30.4) months for palbociclib plus letrozole versus 15.8 (12.9-18.9) months for letrozole (hazard ratio, 0.59 [0.47-0.74]; P<0.001). Median OS was not reached for palbociclib plus letrozole versus 43.4 months (30.0-not estimable) with letrozole (hazard ratio, 0.55 [0.42-0.72]; P<0.001). No interactions between age groups (65-74 and ≥75 years) and treatment groups were observed for rwPFS or OS. Rate of rwBTR was significantly higher for palbociclib plus letrozole (52.4%) versus letrozole (22.1%; odds ratio, 2.0 [1.4-2.7]; P<0.001). CONCLUSION: This analysis demonstrates the effectiveness of palbociclib combination therapy as standard-of-care for older patients with HR+/HER2- MBC in the first-line setting.

Prolonging the life of people with metastatic breast cancer in routine clinical practice by adding palbociclib to an aromatase inhibitor from a real-world database analysis: a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of an article about a study called "P-REALITY X" that was published in the medical journal npj Breast Cancer in October 2022. "P-REALITY X" stands for Palbociclib REAl-world first-LIne comparaTive effectiveness studY eXtended. This study used information from a database to look at whether adding a second treatment (palbociclib) to an aromatase inhibitor (AI) helped people with a certain type of breast cancer to live longer. The type of breast cancer is metastatic hormone receptor-positive/human epidermal growth factor-negative breast cancer, also called HR-positive (or HR+)/HER2-negative (or HER2-) breast cancer. The study used information from the Flatiron Database. This database contains unidentified health care information collected from people seen by doctors in the USA. Only data from people who did not participate in a clinical trial were used. When people are treated outside of a clinical trial, this is called the real-world setting, or routine clinical practice. In clinical trials, people lived longer without their disease worsening if they were treated with palbociclib plus an AI versus being treated with an AI only. Based on the results of clinical trials, treatment with palbociclib plus an AI is already approved and recommended for people with HR+/HER2- breast cancer. This study looked at whether people lived longer if they were treated with palbociclib plus an AI versus being treated with an AI only in routine clinical practice as well. WHAT WERE THE RESULTS?: This study showed that, in routine clinical practice, people treated with the medicine palbociclib plus an AI lived longer than people treated with only an AI. WHAT DO THE RESULTS MEAN?: These results support the continued use of palbociclib plus an AI as the standard first medicine to be given to people with metastatic HR+/HER2- breast cancer. Clinical Trial Registration: NCT05361655 (ClinicalTrials.gov).

The Aetion Coalition to Advance Real-World Evidence through Randomized Controlled Trial Emulation Initiative: Oncology.

Legislative and technological advancements over the past decade have given rise to the proliferation of healthcare data generated from routine clinical practice, often referred to as real-world data (RWD). These data have piqued the interest of healthcare stakeholders due to their potential utility in generating evidence to support clinical and regulatory decision making. In the oncology setting, studies leveraging RWD offer distinct advantages that are complementary to randomized controlled trials (RCTs). They also permit the conduct of investigations that may not be possible through prospective designs due to ethics or feasibility. Despite its promise, the use of RWD for the generation of clinical evidence remains controversial due to concerns of unmeasured confounding and other sources of bias that must be carefully addressed in the study design and analysis. To facilitate a better understanding of when RWD can provide reliable conclusions on drug effectiveness, we seek to conduct 10 RWD-based studies that emulate RCTs in oncology using a systematic, protocol-driven approach described herein. Results of this investigation will help inform clinical, scientific, and regulatory stakeholders on the applications of RWD in the context of product labeling expansion, drug safety, and comparative effectiveness in oncology.

Financial Toxicity among Patients with Breast Cancer during the COVID-19 Pandemic in the United States.

This study reported the prevalence of financial distress (financial toxicity (FT)) and COVID-19-related economic stress in patients with breast cancer (BC). Patients with BC were recruited from the Ciitizen platform, Breastcancer.org, and patient advocacy groups between 30 March and 6 July 2021. FT was assessed with the COmprehensive Score for financial Toxicity (COST) instrument. COVID-19-related economic stress was assessed with the COVID-19 Stress Scale. Among the 669 patients, the mean age was 51.6 years; 9.4% reported a COVID-19 diagnosis. The prevalence rates of mild and moderate/severe FT were 36.8% and 22.4%, respectively. FT was more prevalent in patients with metastatic versus early BC (p < 0.001). The factors associated with FT included income ≤ USD 49,999 (adjusted odds ratio (adj OR) 6.271, p < 0.0001) and USD 50,000-USD 149,999 (adj OR 2.722, p < 0.0001); aged <50 years (adj OR 3.061, p = 0.0012) and 50-64 years (adj OR 3.444, p = 0.0002); living alone (adj OR 1.603, p = 0.0476); and greater depression severity (adj OR 1.155, p < 0.0001). Black patients (adj OR 2.165, p = 0.0133), patients with income ≤ USD 49,999 (adj OR 1.921, p = 0.0432), or greater depression severity (adj OR 1.090, p < 0.0001) were more likely to experience COVID-19-related economic stress. FT was common in patients with BC, particularly metastatic disease, during COVID-19. Multiple factors, especially lower income and greater depression severity were associated with financial difficulties during COVID-19.

Real-world study of overall survival with palbociclib plus aromatase inhibitor in HR+/HER2- metastatic breast cancer.

Data on real-world effectiveness of cyclin-dependent kinase 4/6 inhibitor combination therapy versus endocrine therapy alone are limited. The Flatiron Health Analytic Database was used to assess overall survival (OS) in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (MBC) treated with first-line palbociclib plus an aromatase inhibitor (AI) versus an AI alone in routine US clinical practice. In total, 2888 patients initiated treatment during February 3, 2015-March 31, 2020, with a potential ≥6-month follow-up (cutoff date, September 30, 2020). After stabilized inverse probability treatment weighting, median OS (95% CI) is significantly longer among palbociclib versus AI recipients (49.1 [45.2-57.7] versus 43.2 [37.6-48.0] months; hazard ratio, 0.76 [95% CI, 0.65-0.87]; P < 0.0001). Progression-free survival (95% CI) is 19.3 (17.5-20.7) versus 13.9 (12.5-15.2) months, respectively (hazard ratio, 0.70 [95% CI, 0.62-0.78]; P < 0.0001). These data support first-line palbociclib plus an AI treatment for HR+/HER2- MBC.(Trial number NCT05361655).

Real-World Effectiveness of Palbociclib Plus Letrozole vs Letrozole Alone for Metastatic Breast Cancer With Lung or Liver Metastases: Flatiron Database Analysis.

Background: Cyclin-dependent kinase 4/6 inhibitors are a standard treatment for patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC). However, real-world data on effectiveness in patients with liver or lung metastatic disease is limited. This study compared outcomes of palbociclib plus letrozole versus letrozole alone in patients with HR+/HER2- MBC with lung or liver metastasis treated in routine clinical practice in the United States. Methods: This retrospective analysis used Flatiron Health's database of electronic health records. Women with HR+/HER2- MBC and liver or lung metastasis received first-line palbociclib plus letrozole or letrozole alone between February 2015 and February 2019. Real-world progression-free survival (rwPFS) was defined as time from start of treatment to death or disease progression. Stabilized inverse probability treatment weighting (sIPTW) was used to balance baseline demographic and clinical characteristics between palbociclib plus letrozole versus letrozole cohorts. Cox proportional-hazards models were used to estimate the effectiveness of palbociclib plus letrozole versus letrozole alone in rwPFS and overall survival (OS). Results: The study included 353 patients with lung metastasis, 123 with liver metastasis, and 75 with both. After sIPTW, palbociclib plus letrozole versus letrozole alone was significantlly associated with prolonged rwPFS (hazard ratio (HR), 0.56) and OS (HR, 0.58) (both p<0.001) in all patients. Palbociclib plus letrozole compared with letrozole alone demonstrated a median rwPFS of 16.5 versus 10.5 months, respectively (adjusted HR, 0.52; P<0.001), a median OS of not reached versus 40.3 months (adjusted HR, 0.60; P<0.01) in patients with lung metastasis, and median OS of 30.1 versus 16.8 months (adjusted HR, 0.56; P<0.03 in patients with liver metastasis. In patients with liver metastasis, palbociclib plus letrozole had a median rwPFS of 10.7 months versus 8.0 months in the letrozole alone cohort (adjusted HR, 0.70; P=0.12). Conclusions: In this real-world population, palbociclib in combination with letrozole is associated with improved outcomes compared with letrozole alone for patients with HR+/HER2- MBC and liver or lung metastasis in the first-line setting. The findings support first-line palbociclib in combination with an aromatase inhibitor as standard of care for HR+/HER2- MBC regardless of visceral disease. Clinical Trial Registration: NCT04176354.

Real-World Treatment Patterns and Outcomes of Palbociclib Plus an Aromatase Inhibitor for Metastatic Breast Cancer: Flatiron Database Analysis.

INTRODUCTION: To describe real-world treatment patterns and effectiveness of first-line palbociclib plus an aromatase inhibitor (PAL+AI) and examine the association between PAL initial dose and effectiveness among patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic/advanced breast cancer (HR+/HER2- MBC) in routine clinical practice. PATIENTS AND METHODS: This retrospective analysis used Flatiron Health's database of electronic health records from >280 cancer clinics representing >2.4 million actively treated cancer patients in the United States. Women with HR+/HER2- MBC who received first-line PAL+AI were included. Real-world progression-free survival (rwPFS) was defined as the time from starting PAL+AI to death or disease progression. Real-world best tumor response (rwBTR) was assessed based on the treating clinician's assessment of radiologic evidence for change in disease burden. RESULTS: Of 813 eligible patients, median age was 65.0 years, and median follow-up was 21.0 months. PAL was initiated at 125 mg/d and 75/100 mg/d in 86.5% and 13.5% of patients, respectively. Median duration of PAL+AI was 16.3 months. 43.0% of patients discontinued PAL+ AI; 11.0% discontinued because of toxicity. Median time to subsequent therapy and chemotherapy was 24.6 and 36.6 months, respectively. Median rwPFS was 20.0 months, and best rwBTR rate was 51.9%. Patients starting PAL at 125 versus 75/100 mg/d had longer median rwPFS (27.8 vs. 18.6 months) and higher rwBTR rate (54.0% vs. 40.4%). CONCLUSION: These data demonstrate the benefit of PAL+AI in routine clinical practice and may support the initiation of palbociclib at the recommended dose of 125 mg/d for HR+/HER2- MBC. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: NCT04176354, November 25, 2019.

Real-World Tumor Response of Palbociclib Plus Letrozole Versus Letrozole for Metastatic Breast Cancer in US Clinical Practice.

BACKGROUND: Limited information exists regarding tumor response to palbociclib plus an aromatase inhibitor (AI) versus AI alone in real-world practice. OBJECTIVE: To evaluate the real-world tumor response of palbociclib plus letrozole (PAL+LET) versus LET alone as first-line treatment for patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer (HR+/HER2‒ MBC) in routine US clinical practice. PATIENTS AND METHODS: This retrospective analysis included HR+/HER2‒ MBC patients who initiated PAL+LET or LET as first-line treatment between February 2015 and September 2018 in the Flatiron Health Analytics database. Patients were followed until December 2018. Real-world best tumor response (rwBTR) was determined based on physicians' assessment of radiologic evidence for change in burden of disease. RESULTS: Of the 1383 eligible patients who initiated PAL+LET or LET as first-line therapy in the Flatiron database, 968 patients had ≥ 1 tumor response assessment (662 received PAL+LET and 306 received LET). The rwBTR rate (complete response+partial response) in the first-line setting was 59.8% in the PAL+LET group and 39.2% in the LET group (odds ratio 2.31 (95% CI 1.75‒3.04), P < 0.0001). After 1:1 propensity-score matching, the rwBTR rate was 58.6% in the PAL+LET group versus 39.1% in the LET group (odds ratio 2.21 (95% CI 1.50‒3.25), P < 0.0001). CONCLUSIONS: This real-world analysis demonstrated that HR+/HER2‒ MBC patients were more likely to respond to PAL+LET compared to LET. These findings further showed the effectiveness of PAL+LET therapy in the real-world setting and support the combination as a standard of care for MBC. STUDY REGISTRATION: Pfizer; NCT04176354; registered November 25, 2019.

Palbociclib (Ibrance®; PAL) is a treatment for advanced or metastatic breast cancer (MBC for short). Metastatic means that the cancer has spread from breast tissue to other areas of the body. PAL is taken with medications known as hormone therapy, such as letrozole (LET), to treat people with a type of MBC called hormone receptor‒positive, human epidermal growth factor receptor 2­negative (HR+/HER2‒). Researchers wanted to understand more about how treatment with PAL+LET affected tumor response (i.e., if the tumor shrinks or disappears) in women with HR+/HER2­ MBC. We looked at tumor response to PAL+LET in a real-life setting using anonymous medical record information from a database of about 2.4 million US patients with cancer. This study included 1383 patients with HR+/HER2‒ MBC who started PAL+LET (754 patients) or LET alone (629 patients) as their first MBC treatment from 2015‒2018. Among people who took PAL+LET, 60% people had a tumor response compared with 39% of people who took LET alone. Of the people who took PAL+LET, half of the people lived with their cancer without it getting worse for at least 20 months compared with 15 months for people who took LET alone. These results add to what is known about PAL+LET treatment based on routine clinical practice and clinical trials. Both types of information provide support for PAL+LET treatment as the standard care for women with HR+/HER2‒ MBC. Video Abstract (MP4 90112 kb).

Prognostic Factors for Overall Survival in Patients with Hormone Receptor-Positive Advanced Breast Cancer: Analyses From PALOMA-3.

BACKGROUND: This analysis investigated whether baseline characteristics affect the survival benefit derived from palbociclib-fulvestrant and the optimal timing of cyclin-dependent kinase 4/6 inhibitor therapy for advanced breast cancer (ABC) in patients from PALOMA-3. PATIENTS AND METHODS: In total, 521 patients were randomized 2:1 to receive palbociclib (125 mg/day, 3/1 schedule)-fulvestrant (500 mg, intramuscular injection, on days 1 and 15 of cycle 1, and then day 1 of each subsequent cycle) or matching placebo-fulvestrant. Median overall survival (OS) and progression-free survival were estimated using the Kaplan-Meier method. RESULTS: Multivariable analysis identified endocrine sensitivity, nonvisceral disease, no prior chemotherapy for ABC, and Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 as significant prognostic factors for OS. Patients without chemotherapy for ABC had fewer prior lines of treatment in any setting and in the ABC setting versus patients with prior chemotherapy for ABC (two or fewer prior systemic therapies: 69% vs. 42%; no more than one prior line for ABC: 82% vs. 33%, respectively). Median OS was prolonged with palbociclib-fulvestrant in patients without prior chemotherapy for ABC (39.7 vs. 29.5 months; hazard ratio, 0.75; 95% confidence interval [CI]: 0.56-1.01) and was similar in patients with prior chemotherapy for ABC (25.6 vs. 26.2 months; hazard ratio, 0.91 [95% CI: 0.63-1.32]) versus placebo-fulvestrant. CONCLUSION: Prognostic factors for OS included endocrine sensitivity, nonvisceral disease, ECOG PS of 0, and no prior chemotherapy for ABC. Exploratory analyses suggest improved OS with palbociclib-fulvestrant versus placebo-fulvestrant in patients with no prior chemotherapy for ABC, prior endocrine sensitivity, and fewer prior regimens of systemic therapy. (Clinical trial identification number: NCT01942135). IMPLICATIONS FOR PRACTICE: Prognostic factors for overall survival in HR+/HER2- advanced breast cancer (ABC) include the absence of prior chemotherapy in the advanced setting, endocrine sensitivity, nonvisceral disease, and an ECOG performance status of 0. Improved overall survival benefit was observed with palbociclib-fulvestrant versus placebo-fulvestrant in patients (regardless of menopausal status or visceral involvement) with no prior chemotherapy for ABC, with prior endocrine sensitivity, and fewer prior regimens of systemic therapy. Progression-free survival was prolonged with palbociclib across subgroups (regardless of chemotherapy exposure in ABC). These exploratory findings suggest that patients may receive greater clinical benefit from palbociclib-fulvestrant if they receive the combination before chemotherapy in the advanced setting.

Age Is Just a Number: Considerations for Older Adults in Cancer Clinical Trials.

Older adults continue to be underrepresented in cancer clinical trials, despite most cancer occurrence peaking in the later decades of life. Consequently, diagnostic and management strategies are commonly extrapolated from data on younger patients, thus challenging the delivery of informed cancer care in this patient population. Several recommendations and calls to action have been released by cancer societies, advocacy organizations, and regulatory agencies to guide inclusion of older adults in clinical trials. Effective implementation, however, requires awareness and close collaboration between all stakeholders involved in the clinical trial journey. We herein provide insights and experience from a drug developer on key considerations to optimize participation and retention of older adults in cancer clinical trials and discuss those under 4 key domains: trial eligibility and design, assessments and endpoints, patients and oncologists, and data reporting.